Background: Transforaminal epidural steroid injections are known to reduce inflammation by inhibiting synthesis of various proinflammatory mediators and have been used increasingly. The anti-inflammatory properties of opioids are not as fully understood but apparently involve antagonism sensory neuron excitability and pro-inflammatory neuropeptide release. To date, no studies have addressed the efficacy of transforaminal epidural morphine in patients with radicular pain, and none have directly compared morphine with a tramadol for this indication. The aim of this study was to compare morphine and tramadol analgesia when administered via epidural injection to patients with lumbar radicular pain. Methods: A total of 59 patients were randomly allocated to 1 of 2 treatment groups and followed for 3 months after procedure. Each patient was subjected to C-arm guided transforaminal epidural injection (TFEI) of an affected nerve root. As assigned, patients received either morphine sulfate (2.5 mg/2.5 ml) or tramadol (25 mg/0.5 ml) in combination with 0.2% ropivacaine (1 ml). Using numeric rating scale was subsequently rates at 2 weeks and 3 months following injection for comparison with baseline. Results: Both groups had significantly lower mean pain scores at 2 weeks and at 3 months after treatment, but outcomes did not differ significantly between groups. Conclusions: TFEI of an opioid plus local anesthetic proved effective in treating radicular pain. Although morphine surpassed tramadol in pain relief scores, the difference was not statistically significant.